can't open EXCEL_X export file when ExportMenu inside ActiveForm

[aikon2]

I have TabularForm and ActiveForm for submit, at toolbar ExportMenu::widget. I can download/export to all format, but:

• can't open file FORMAT_EXCEL_X with messege Excel cannot open the file ... because the file format or file extension is not valid. Verify that the file has not been corrupted and that the file extension matches the format of the file.,
• show code Ôªø in first cell for file FORMAT_EXCEL

I guess because ExportMenu::widget inside ActiveForm and effect for this widget. any solution in this case?

<?php ActiveForm::begin([...]); echo TabularForm::widget([ ... 'gridSettings' => [ 'toolbar' => [ ['content' => ExportMenu::widget([ 'dataProvider' => $dataProvider, 'columns' => [...], ]) .... ] ]) ActiveForm::end([]) ?>